Myocardial preservation during cardiopulmonary bypass (CPB) operations with ischemic aortic crossclamp continues to be a topic of clinical and experimental investigations. Our group and others have investigated the acute hemodynamic effects of several methods currently being used to protect the myocardium including coronary perfusing, hypothermic ischemic arrest, and potassium-based cardioplegia. However, to date, results of chronic studies evaluating different methods of myocardial preservation with reference to left ventricular fumction and pathology are inconclusive and not amenable for comparison. Our laboratory has ongoing experimental projects investigating the acute and chronic pathologic and hemodynamic effects of several different methods of myocardial preservation.